function preloadLogos() {
	$(".logos div img").each(function(){
		var img = $(this).attr("f");	
		$("<img>").attr("src", "../images/logos/" + img + "-color.png");
	});
}

$(document).ready(function() {
	preloadLogos();
	$(".logos div img").hover(
			function() {
				var img = $(this).attr("f");	
				this.src = "/images/logos/" + img + "-color.png";
			}
			,
			function() {
				var img = $(this).attr("f");	
				this.src = "/images/logos/" + img + "-gray.png";
			}
		)
});